That was Jan Brady’s complaint — about how everybody favored her older sister. Perhaps Jan invoked Marcia’s name in an entirely different way — a bodice-ripping way — when the cameras were off. At least that’s what the actress who played Marcia claims in a new book. For the record, I don’t believe it, because this revelation is intended to sell books and it follows in the tradition of Greg Brady claiming in his book to have gone on a date with the actress who played his mother, Florence Henderson. Still, if Eve Plumb confirms Marcia McCormick’s claim, it will simply be the best showbiz story of all time.